Structural, magnetic and dielectric properties of pure and Dy-doped Co3O4 nanostructures for the electrochemical evolution of oxygen in alkaline media

In this study, spinel-type cobalt oxide (Co3O4) and Co3-xDyxO4 (x = 0.04 and 0.05 molar ratio) nanoparticles were synthesized via combustion method at 700 °C. Crystallite nature, phase purity and thermal analysis of the prepared compounds were investigated by PXRD, FT-IR and TGA techniques. Structural analyses were performed by the FullProf program employing profile matching with constant scale factors. The results showed that the patterns had a main cubic structure with space group of Fd3m. The cell parameter data calculated by rietveld analysis showed that the cell parameters were nearly constant. The morphological and structural properties of the obtained materials were examined by FESEM and TEM images. Besides, the magnetic measurements of Co3O4 and Co3-xDyxO4 nanoparticles were performed by vibration sampling magnetometer (VSM). Coercivity (Hc) and remanent magnetization (Mr) were found to be reduced in Dy3+ doped Co3O4 while saturation magnetization (Ms) was increased moderately. The effect of dysprosium ion addition was also studied using cyclic voltammetry (CV) for the oxygen evolution reaction in an alkaline environment. The obtained data showed that the presence of Dy3+ exhibited a much higher oxygen evolution activity and lower over potential compared to Co3O4.